An update from the Municipality of Wood Buffalo later in the evening indicated that the fire was continuing to claim homes and had destroyed a new school.

Authorities said there had been no known casualties from the blaze itself, but deaths were reported in at least one car crash when people were evacuating.

Chelsie Klassen, a spokeswoman for the Canadian Association of Petroleum Producers, said all large oil sands facilities would be properly shut to minimise the damage.

'Heartbreaking'

Alberta Premier Rachel Notley flew up to survey the situation, while officials in the evacuation centre had to bolt to the south of the city as flames edged closer.

Notley tweeted pictures of the fire from above. "The view from the air is heartbreaking," she wrote.

Notley said about 10,000 evacuees moved north where oil sands work camps were being pressed into service to house evacuees. The bulk of the evacuees fled south to Edmonton and elsewhere, and officials said they eventually would like to move everyone south.

Canadian Prime Minister Justin Trudeau said, while the full extent of the damage wasn't yet known, that it was "absolutely devastating" and that there was loss on a scale that was hard to imagine.

Trudeau said he had offered the province his government's full support.